From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: ABS_MT_TOUCH_MAJOR metric Date: Thu, 22 May 2014 10:23:53 -0700 Message-ID: <20140522172353.GA1984@core.coreip.homeip.net> References: <537DD98C.5090800@cypress.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pb0-f47.google.com ([209.85.160.47]:58535 "EHLO mail-pb0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751061AbaEVRX5 (ORCPT ); Thu, 22 May 2014 13:23:57 -0400 Received: by mail-pb0-f47.google.com with SMTP id rp16so2797585pbb.34 for ; Thu, 22 May 2014 10:23:57 -0700 (PDT) Content-Disposition: inline In-Reply-To: <537DD98C.5090800@cypress.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Ferruh Yigit Cc: "linux-input@vger.kernel.org" , Henrik Rydberg Hi Ferruh, On Thu, May 22, 2014 at 02:03:40PM +0300, Ferruh Yigit wrote: > Hi, > > What is the metric of ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR events? > > The Linux documentation > says: > "The length of the major axis of the contact. The length should be given > in surface units. ..." > > What does "surface units" means, is it millimeter or pixels? It is whatever unit the device reports, similarly to ABS_MT_POSITION_X and ABS_MT_POSITION_Y. Userspace can use EVIOCGABS to map device units onto common units. >>From include/uapi/linux/input.h (struct input_absinfo): * Resolution for main axes (ABS_X, ABS_Y, ABS_Z) is reported in * units per millimeter (units/mm), resolution for rotational axes * (ABS_RX, ABS_RY, ABS_RZ) is reported in units per radian. Hope this helps. -- Dmitry